Liquid injector assembly with a flanged connector connection

ABSTRACT

A system for injecting from an injector into a duct of an engine system is provided. The system may include a first flange on a duct connection side, a second flange on an injector connection side, a stand-off separating the first flange from the second flange to form an air gap therebetween, and a seal offset from at least one of the first and the second flanges and located within the airgap and between the first flange and the second flange.

CROSS REFERENCE TO RELATED APPLICATIONS

This present application is a divisional of U.S. application Ser. No.12/575,803, filed Oct. 8, 2009, filed Oct. 8, 2009, which is now U.S.Pat. No. 8,191,356, which is a continuation of U.S. application Ser. No.12/053,048 filed Mar. 21, 2008, which is now U.S. Pat. No. 8,127,538 andentitled “Liquid Injector Assembly with a Flanged Connector Connection”,naming Dwayne Pollitt, Furqan Zafar Shaikh, Scott Donald Cooper, MichaelLevin, John Paul Bogema, Bret Alan Zimmerman and Gary Scott Nichols asinventors, the entire contents of each of which are incorporated hereinby reference for all purposes.

BACKGROUND AND SUMMARY

Selective Catalyst Reduction (SCR) catalysts and liquid reductant (e.g.,hydrocarbon or urea solution) injected into engine exhaust ducts may beused for reducing engine-out NOx emissions. However, heat from theengine exhaust may cause reductant injectors to overheat and may causesolids to deposit on the injector tip. The solid deposits may in turnresult in clogging of the injector orifice.

One approach used to address injector overheating may be to use a smallV-band clamp for connecting the injector and its mounting structure tothe exhaust passage. The V-band serves to potentially insulate theinjector from engine exhaust heat, thereby reducing solid depositbuildup.

However, the inventors herein have recognized that connecting theinjector to the mounting structure using a V-band clamp may requirespecial tools and may be too cumbersome to allow fast and easy assemblyin a mass production environment. Likewise, premature degradation of theV-band clamp, due to assembly installation variation, for example, mayincrease exhaust leakage.

A system for injecting from an injector into a duct of an engine systemis provided herein to at least partially address above mentioned issues.The system may include a first flange on a duct connection side, asecond flange on an injector connection side, a stand-off separating thefirst flange from the second flange to form an air gap therebetween, anda seal offset from at least one of the first and the second flanges andlocated within the air gap and between the first flange and the secondflange.

In this way, it is possible to obtain a reliable, robust, andtime-efficient connection of the injector with reduced contact surfacearea between potentially high temperature injector components and theinjector via the seal positioned in the air gap formed by the stand-off.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an example engine 10 in which aninjector assembly for injecting liquid according to the presentdisclosure may be applied.

FIG. 2A is a side view of a first embodiment of an injector assembly,with an injector module of the injector assembly detached from anexhaust duct housing of the injector assembly.

FIG. 2B is a side view of the injector assembly of FIG. 2A, with theinjector module attached to the exhaust duct housing.

FIG. 2C is a side perspective view of the injector module of theinjector assembly of FIGS. 2A & 2B, showing details of an injectormodule flange of the injector module.

FIG. 2D is a side perspective view of the exhaust duct housing of theinjector assembly of FIGS. 2A & 2B, showing details of an exhaust ducthousing flange of the injector module.

FIG. 3A is a side perspective view of an injector module of a secondembodiment of the injector assembly.

FIG. 3B is a side perspective view of an exhaust duct housing for theinjector module of FIG. 3A.

FIG. 4A is a side perspective view of an injector module of a thirdembodiment of the injector assembly

FIG. 4B is a side perspective view of an exhaust duct housing for theinjector module of FIG. 4A.

DETAILED DESCRIPTION

FIG. 1 is a schematic diagram of example environment in which aninjector assembly for injecting liquid in a high temperatureenvironment, such as injecting a liquid reductant into an engine exhaustfor reducing NOx in a Selective Catalytic Reduction (SCR) catalyst, maybe implemented. However, the various configurations described herein maybe applied to other injection configurations, if desired, such as forinjecting fuel into an intake duct, for example.

Internal combustion engine 10, comprising a plurality of cylinders, onecylinder of which is shown in FIG. 1, is controlled by electronic enginecontroller 12. Engine 10 includes combustion chamber 30 and cylinderwalls 32 with piston 36 positioned therein and connected to crankshaft40. Combustion chamber 30 is shown communicating with intake manifold 44and exhaust manifold 48 via respective intake valve 52 and exhaust valve54. Intake manifold 44 is also shown having fuel injector 80 coupledthereto for delivering liquid fuel in proportion to the pulse width ofsignal FPW from controller 12. Both fuel quantity, controlled by signalFPW and injection timing are adjustable. Fuel is delivered to fuelinjector 80 by a fuel system including a fuel tank, fuel pump, and fuelrail (not shown).

Controller 12 is shown in FIG. 1 as a microcomputer including:microprocessor unit 102, input/output ports 104, read-only memory 106,random access memory 108, and a conventional data bus. Controller 12 isshown receiving various signals from sensors coupled to engine 10, inaddition to those signals previously discussed, including: enginecoolant temperature (ECT) from temperature sensor 112 coupled to coolingsleeve 114; a measurement of manifold pressure (MAP) from pressuresensor 116 coupled to intake manifold 44; a measurement (AT) of manifoldtemperature from temperature sensor 117; an engine speed signal (RPM)from engine speed sensor 118 coupled to crankshaft 40.

Oxidation catalyst 13 is coupled to the exhaust manifold 48 downstreamof engine 10 and may be a precious metal catalyst, such as platinumcatalyst. A Selective Catalytic Reduction (SCR) Catalyst 14 for reducingNOx in an oxygen rich environment is coupled downstream of the oxidationcatalyst 13.

A reductant delivery system 16 including an injector assembly (examplesof which are illustrated in FIGS. 2 to 4) is coupled to the exhaust gasmanifold between the oxidation catalyst and the SCR catalyst 14 forsupplying a reductant to the NOx reducing catalyst in Catalyst 14. Thereductant may, for example, be fuel (hydrocarbon) or aqueous urea, etc.

It should be appreciated the above described example internal combustionengine 10 is non-limiting. Engine 10 may include a diesel engine thatproduces a mechanical output by combusting a mixture of air and dieselfuel. Alternatively, engine 10 may include other types of engines suchas gasoline burning engines, among others. Further, engine 10 may beconfigured in a propulsion system for a vehicle. Alternatively, engine10 may be operated in a stationary application, for example, as anelectric generator. While exhaust system 10 may be applicable tostationary applications, it should be appreciated that exhaust system 10as described herein, is particularly adapted for vehicle applications.

FIGS. 2 to 4 illustrate various non-limiting embodiments of an injectorassembly 200 for injecting liquid from an injector into a hightemperature air duct. The injector assembly 200 may be used in engineexhaust for delivering liquid reductant, such as urea or hydrocarbon,for reducing NOx in a SCR catalyst. The injector assembly 200 may alsobe used in other high temperature environments.

In particular, FIGS. 2A to 2D illustrate a first embodiment, FIGS. 3Aand 3B illustrate a second embodiment, and FIGS. 4A to 4B illustrate athird embodiment of the injector assembly 200. For the sake ofconvenience, similar parts are labeled the same for all threeembodiments. Also note that different elements of the differentembodiments may be combined with one another.

The injector assembly 200 may include an injector module 202 on aninjector connection side of the injector assembly 200, an exhaust ducthousing 204 mounted on a wall 206 of an engine exhaust 208 on a ductconnection side of the injector assembly 200, and a flanged connectionportion 210 for coupling injector module 202 to exhaust duct housing204.

The flanged connection portion 210 may include an injector module flange212 coupled to the injector module 202, and an exhaust duct housingflange 214 coupled to the exhaust duct housing 204. The flangedconnection portion 210 may additionally include a stand-off 218separating the injector module flange 212 from the exhaust duct housingflange 214 to form an air gap 219 therebetween. The flanged connectionportion 210 may further include a seal 225 that is offset from one, orboth, of the injector module flange 212 and the exhaust duct housingflange 214.

The injector module flange 212 and the exhaust duct housing flange 214may be of various shapes and designs. For example, the injector moduleflange 212 and the exhaust duct housing flange 214 may be substantiallyflat, as shown in FIGS. 1 and 2. Alternatively, either the injectormodule flange 212 or the exhaust duct housing flange 214 may curvetoward exhaust at the edge to form a cover 223 for shielding theconnection junction formed between the injector module flange 212 andthe exhaust duct housing flange 214 when the injector module flange 212is mounted on the exhaust duct housing flange 214. The cover 223 mayform a tight fit or reserve an air gap for fluid communication betweenthe junction between the injector module flange 212 and an outsideenvironment. FIGS. 4A to 4B show that the injector module flange 212curves toward exhaust at the edge to form a cover 223 that fits over theexhaust duct housing flange 214.

The seal 225 may be located within the air gap and between the injectormodule flange 212 and the exhaust duct housing flange 214. The seal 225may also form an integral part of either or both of the injector moduleflange 212 and the exhaust duct housing flange 214. For example, theseal 225 may be installed/retained to the injector module flange 212and/or the exhaust duct housing flange 214. The seal 225 forms a firstprotrusion, and it may include a reduced sealing surface 220 and areason 229, which forms a second protrusion, thus reducing heat transferbetween the exhaust duct housing 204 to the injector module 202. In thisway, over heating of the injector module 202 may be reduced.

The stand-off 218 may be various suitable parts that help to set apartthe injector module flange 202 and the exhaust duct housing module 204to create the air gap 219. For example, the stand-off 218 is shown inFIG. 2D to form a circular sleeve around at least one bolt 234 of thefastening structure 216. It is also possible for the exhaust ducthousing 204 to include the standoff 218. The stand-off 218 may form anintegral part of the injector module flange 212, the exhaust ducthousing flange 214, and/or one or more of bolts 234 that form afastening structure 216 for fastening the injector module flange 212 andthe exhaust duct housing flange 214. The standoff 218 may includevarious suitable dimensions. In one example shown in FIG. 4B, thestand-off 218 may have a height of 10 mm, creating an air gap 219 havinga height (H) of 10 mm. However, various other dimensions may be used;for example, the height of the stand-off may be between 5 and 15 mm,resulting in a corresponding range of air gaps.

The air gap 219 created may serve to reduce heat transfer from theexhaust duct housing 204 to the injector module 202 because of itsrelatively low thermal conductivity. The air gap 219 may be in a fluidcommunication with a cooler surrounding air, allowing the coolersurrounding air to circulate within the air gap 219 to cool theconnection portion 210 to reduce heat transfer from the exhaust ducthousing 204 to the injector module 202.

The flanged connection portion 210 may also include a fasteningstructure 216 configured to fasten the injector module flange 212 andthe exhaust duct housing flange 214. In some examples, the fasteningstructure 216 may fasten the injector module flange 212 to the exhaustduct housing flange 214 in cooperation with the stand-off 218. Thefastening structure 216 may be various suitable fastening structures 216for fastening the injector module 202 to the exhaust duct housing 204.For example, the fastening structure 216 may include one or morebolt-nut fastening structures, such as two flange bolt-nut pairs. Thefastening structure 216 may also include one or more holes for receivingthe bolt-nut pairs. In one example and as illustrated in FIG. 2A to 2D,the fastening structure 216 may include a pair of bolts 235 coupled tothe exhaust duct housing flange 214, a pair of bolt orifices 236 formedin the injector module flange 212 for receiving the pair of bolts 234,and a pair of nuts 238 configured to be fastened onto the pair of bolts234.

The injector assembly 200 may further include an alignment feature 221for aligning the injector module 202 and the exhaust duct housing 204 toensure a consistent rotational positioning of the injector module 202onto the exhaust duct housing 204, and/or a poka-yoke feature 222 toensure reliable assembly of the injector module 202 and the exhaust ducthousing 204. The alignment feature 221 and the poka-yoke feature 222 maybe served by a single feature or may be served by separate features ofthe injector assembly 200. The alignment structure 221 may includevarious suitable structures or features that align the injector module202 and the exhaust duct housing 204, for example by aligning theinjector module flange 212 to the exhaust duct housing flange 214. Thealignment feature 221 may include an alignment tab/notch structure. Asshown in FIGS. 3A & 3B, the alignment tab/notch structure may include analignment tab 228 formed on the injector module flange 212 and analignment notch 226 formed on the exhaust duct housing flange 214, withthe alignment notch 226 sized to receive the alignment tab 228.

The poka-yoke feature 222 may include various suitable structures offeatures that help to provide reliable assembly of the injector module202 and the exhaust duct housing 204. For example, the poka-yoke feature222 may include an asymmetrically positioned pin-hole structure. Thepin-hole structure may include a pin 232 positioned on and may be anintegral part of the exhaust duct housing flange 214, and an similarlyoff-centered and non-symmetrically positioned hole 234 formed in theinjector module flange 212 for receiving the pin, as shown in FIG. 2C,2D as well as in FIGS. 4A and 4B. For another example, the poka-yokefeature 222 may include certain design dimensions, such asasymmetrically shaped and matching injector module flange 212 andexhaust duct housing flange 214, to assure the injector module 202 andthe exhaust duct housing 204 are assembled the correct way.

It should be appreciated that the injector assembly 200 may includeother structures or features that are not described above, such as afinned body, clamp, one or more connectors, graphite bush, and one ormore lock washers, for example.

In this way, it is possible to achieve a relatively simple and reliableinstallation procedure. The installation procedure may include, forexample, pushing the injector module 202 over bolts or studs positionedon injector module flange 204, and torquing nuts onto the bolts. Thisinstallation procedure may allow for a single-hand mounting of theinjector module 202 onto the exhaust duct housing 204 and a hand-freefastening of the fastening structure 216.

It will also be appreciated that the configurations disclosed herein areexemplary in nature, and that these specific embodiments are not to beconsidered in a limiting sense, because numerous variations arepossible. For example, while the above example approaches may be used toavoid a connection using a V-band clamp, in some elements of the aboveapproaches may be combined with a V-band clamp to provide certaindesired operation. Thus, the subject matter of the present disclosureincludes all novel and nonobvious combinations and subcombinations ofthe various systems and configurations, and other features, functions,and/or properties disclosed herein.

The following claims particularly point out certain combinations andsubcombinations regarded as novel and nonobvious. These claims may referto “an” element or “a first” element or the equivalent thereof. Suchclaims should be understood to include incorporation of one or more suchelements, neither requiring nor excluding two or more such elements.Other combinations and subcombinations of the disclosed features,functions, elements, and/or properties may be claimed through amendmentof the present claims or through presentation of new claims in this or arelated application. Such claims, whether broader, narrower, equal, ordifferent in scope to the original claims, also are regarded as includedwithin the subject matter of the present disclosure.

The invention claimed is:
 1. An exhaust duct housing comprising: anexhaust duct housing flange with a centrally positioned hole; a firstprotrusion extending upward from the exhaust duct housing flange, thefirst protrusion concentrically arranged about the hole; a secondprotrusion extending upward from the first protrusion and terminatingwith a sealing surface, where the second protrusion is concentricallyarranged around the hole, and the second protrusion extends furtherupward than the first protrusion; at least two stand-offs positionedsymmetrically on opposite sides of the hole and aligned on a common axiswith the hole, where each of the at least two stand-offs form a circularsleeve concentrically arranged around a bolt, and where the at least twostand-offs are integral with the exhaust duct housing flange; and a pinpositioned between the hole and one of the at least two stand-offs,where the pin is offset from the common axis.
 2. The exhaust ducthousing of claim 1, where the pin is integral with the exhaust ducthousing flange.
 3. The exhaust duct housing of claim 1, furthercomprising a hole configured to receive the pin therethrough.
 4. Theexhaust duct housing of claim 1, where a height of each of the at leasttwo stand-offs is within a range of 5-15 mm.